text: Four metals are active as catalysts for the Fischer–Tropsch process: iron, cobalt, nickel, and ruthenium. Since FT process typically transforms inexpensive precursors into complex mixtures that require further refining, FT catalysts are based on inexpensive metals, especially iron and cobalt.  Nickel generates too much methane, so it is not used.
  Typically, such heterogeneous catalysts are obtained through precipitation from iron nitrate solutions. Such solutions can be used to deposit the metal salt onto the catalyst support (see below).  Such treated materials transform into active catalysts by heating under CO, H or with the feedstock to be treated, i.e., the catalysts are generated in situ.  Owing to the multistep nature of the FT process, analysis of the catalytically active species is challenging. Furthermore, as is known for iron catalysts, a number of phases may coexist and may participate in diverse steps in the reaction. Such phases include various oxides and carbides as well as polymorphs of the metals. Control of these constituents may be relevant to product distributions. Aside from iron and cobalt, nickel and ruthenium are active for converting the CO/H mixture to hydrocarbons.  Although expensive, ruthenium is the most active of the Fischer–Tropsch catalysts in the sense that It works at the lowest reaction temperatures and produces higher molecular weight hydrocarbons. Ruthenium catalysts consist of the metal, without any promoters, thus providing relatively simple system suitable for mechanistic analysis. Its high price preclude industrial applications. Cobalt catalysts are more active for FT synthesis when the feedstock is natural gas. Natural gas has a high hydrogen to carbon ratio, so the water-gas shift is not needed for cobalt catalysts. Cobalt-based catalysts are more sensitive than their iron counterparts.
  Illustrative of real world catalyst selection, high-temperature Fischer–Tropsch (HTFT), which operates at 330–350 °C, uses an iron-based catalyst. This process was used extensively by Sasol in their coal-to-liquid plants (CTL). Low-temperature Fischer–Tropsch (LTFT)  uses an iron- or cobalt-based catalyst. This process is best known for being used in the first integrated GTL-plant operated and built by Shell in Bintulu, Malaysia.